In a printing system such as described above, the printer is connected to the data terminal, which is communicatively connected to the Internet, and communication between the printer and the server passes through the data terminal (see, for example, PTL 1).
When the Internet connection becomes unstable in a system that connects a server and a data terminal over the Internet and uses an application program that runs on the server from the data terminal, operation of the application program used by the data terminal becomes unstable. Addressing this problem, PTL 2, for example, describes a system that connects the server and a proxy server over the Internet, connects the proxy server and the data terminal over a LAN, downloads the application program from the server to the proxy server and runs the program on the proxy server, and uses the application program running on the proxy server from the data terminal. Because the data terminal uses an application program running on a proxy server connected to a LAN in this system, operation of the application program used by the data terminal is stable regardless of the state of the Internet connection.